After the first practice of San Diego Chargers training camp, the team is already calling around about adding a veteran quarterback after backup Charlie Whitehurst injured his left knee, reports Michael Gehlken of the San Diego Union-Tribune.

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An easy option for the Chargers would be to break the "In Case Of Emergency, Break Glass" case containing Billy Volek, who was a mainstay at the No. 2 job before the Bolts shipped Whitehurst to the Seattle Seahawks in 2010. The 36-year-old Volek remains a free agent and, according to Gehlken, plans to continue his career. Volek has not started an NFL game since 2005 and attempted just 44 passes with one touchdown and two interceptions in his six seasons in San Diego.

Whitehurst returned to the Chargers in March, signing a two-year, $3.05 million contract. The only other quarterback on the Chargers' roster is Jarrett Lee, an undrafted free agent out of LSU. If Whitehurst's injury turns out to be more serious, or if the club wants to bring in more competition for the backup job behind Philip Rivers, experienced free-agent options include former first-round picks Kyle Boller and J.P. Losman.

UPDATE: The Chargers wasted little time bringing in a veteran backup, announcing later Friday that Boller has been signed to a one-year contract.